Currently, there are several types of materials that are used in building construction. Most commonly used are stone, wood, bricks, concrete, metal, and plaster and other materials. Many construction materials are available individually for assembly at the construction site, such as stone, wood, bricks etc., while others are assembled from pre-fabricates in a production factory, and then transported to the construction site as subassemblies, mostly in the form of various panels.
Pre-fabricated panels, made of steel reinforced concrete, have been widely used in the large-scale construction of houses and buildings. Panels, with insulating and other surface layers, are used to build complete houses, including roofs, ceilings, floors and backer-boards for ceramic tiles, thin bricks, thin stones, synthetic or natural stucco used in kitchens, bathrooms, shower rooms, corridors or any places that require water resistance and impact resistance. For wall systems, a wall joist structure (columns) is constructed and pre-fabricated panels may be attached to the joists. For flooring or roofing, a joist structure of beams is assembled and the pre-fabricated panels may be attached to the joists. For decking applications, pre-fabricated cement panels may be provided with a support structure to reduce the number of beams required to support the decking. However, cement panels can be extremely heavy.
Many pre-fabricated panels also incorporate pre-stressed and rebar reinforced cement/concrete products to increase high tensile strength and high bending strength. For example, high performance composite materials such as reinforcing fibers may be added to the surface of cement-based products to increase bending stiffness as described by Jinno et al., U.S. Pat. No. 6,330,776 entitled “Structure For Reinforcing Concrete Member And Reinforcing Method.” Interior reinforcing metal strips or cross-bars can also be used to increase bending stiffness as disclosed, for example, by William H. Porter, U.S. Pat. No. 5,842,314, entitled “Metal Reinforcement of Gypsum, Concrete or Cement Structural Insulated Panels”; U.S. Pat. No. 6,269,608, entitled “Structural Insulated Panels For Use With 2×Stick Construction”; U.S. Pat. No. 6,408,594, entitled “Reinforced Structural Insulated Panels With Plastic Impregnated Paper Facings”; Meier et al., U.S. Pat. No. 5,937,606, entitled “Securing Of Reinforcing Strips”; and Billings et al., U.S. Pat. No. 6,230,409, entitled “Molded Building Panel and Method Of Construction”.
While the bending stiffness can be increased by reinforcing metal strips or cross-bars embedded in pre-fabricated panels, the overall weight of the pre-fabricated panels with sufficient stiffness and high bending strength remains a challenge. This is because embedding structural frameworks (metal strips or cross-bars) into cement can result in a heavy, thick construction using more cement product than is required. As a result, many panels still require a relatively thick plate for high load bearing applications. Moreover, materials used for prefabricated panels have been less than satisfactory in many respects, including their relatively high cost, heavy weight, structural deficiencies, and lack of resistance to elements.
Therefore, a need exists for a new structural building element, a lightweight pre-fabricated panel/tile provided with high stiffness, high bending strength without increasing overall weight for construction applications such as flooring, roofing, decking, bridge surface, and wall systems.